1. Field of the Invention
The invention relates to a heat dissipating device for electronic components, more particularly to a heat dissipating device constituted by a plurality of metal plates which are disposed next to each other to form a stack.
2. Description of the Related Art
Heat-dissipating devices fabricated from aluminum extruded plate sections are commonly used in cooling electronic components, such as integrated circuit modules, since the manufacturing process thereof is simple and inexpensive. A typical heat-dissipating device has a plurality of thin metal plates with base plate portions arranged in a stack and coupled together by welding, screwing or riveting. Cooling fin portions extend in parallel from the base plate portions and are spaced apart from each other to define gaps for passage of an air flow. The base plate portions are adapted to contact a heat generating device to carry off heat by heat-conduction, whereas the fin portions serve to provide a heat transfer surface area to transfer heat to a cooling air flow by heat convection. The cooling efficiency of such heat dissipating devices depends on the heat transfer surface area, the orientation and the degree of separation of the fin plate portions. Generally, the ratio of the area of the fin plate portions to the area of the base plate portion in each plate is kept to be high in order to obtain a sufficient heat transfer area. The separation of the fin plate portions is arranged to be as large as possible so as to permit a substantial amount of air to flow therethrough.
In a copending U.S. patent application Ser. No. 09/379,069 and filed by the applicant of this application, there is disclosed a heat dissipating device in which fin plate portions extend divergingly from a stack of base plate portions to increase the measure of separation between the fin plate portions and to permit a sufficient amount of air to flow through the surface of the fin plate portions. The base plate portions are polygonal and include four sides or six sides. The fin plate portions extend from the base plate portions from one side or more than one side of the latter and have a large surface area as compared to the base plate portions. Although the heat dissipating devices disclosed in the aforesaid copending application can provide an efficient heat transfer due to the divergent separation and the increased heat transfer surface area of the fin portions, the four-sided or six-sided base plate portions can form a bulky body when arranged in a stack. In view of a recent trend toward miniaturization of electronic components, a heat-dissipating device which has a compact size but is still efficient for dissipating heat is desirable.
A primary object of the present invention is to provide a heat dissipating device of the above-mentioned type which has a high ratio of the area of fin plate portions to the area of base plate portions so that a stack part formed by the base plate portions is compact while the fin plate portions maintain a sufficient heat transfer surface area.
Another object of the present invention is to provide a heat dissipating device with a stack of base plate portions which has a reduced size but can still provide a sufficient contact surface to contact a heat generating object.
Accordingly, a heat dissipating device of the present invention comprises a plurality of plates each having a three-sided base plate portion and a pair of fin plate portions. The base plate portion has a contact side adapted to contact a heat generating object, and two opposite sides forming an angle therebetween and extending to two opposite ends of the contact side. The base plate portions of the plates are disposed in parallel and next to each other to form a stack. The fin plate portions of each plate respectively extend outward from the opposite sides of the base plate portion. The fin plate portions of the plates are bent respectively from the base plate portions of the plates to diverge outward and to form air passages therebetween.